1. Field of the Invention
The present invention relates to an auxiliary appliance for syringe fixation, and more specifically, it relates to the structure of an auxiliary appliance for syringe fixation for attaching a syringe which is filled up with a contrast medium to an injection head in a medical field.
2. Description of the Background Art
In recent years, various means for testing functions of human bodies have been developed. One of such means is angiography employing a high-speed scan CT for diagnosing the functions of circulatory organs of a human body. The angiography employing a CT is adapted to inject a contrast medium into a patient's body for diagnosing the functions of the circulatory organs through the contrast medium which is injected into the patient's body with the CT.
FIG. 11 shows an injection head 10, which is generally employed for injecting a contrast medium into a human body. A syringe 300 which is previously filled up with a contrast medium is attached to the injection head 10, and a piston 300d provided in the syringe 300 is gradually moved toward the forward end of the syringe 300 with a plunger 11 which is provided in the injection head 10, as shown in FIG. 12. Thus, the contrast medium is injected into the human body through a tube 301 which is attached to the forward end of the syringe 300 and a catheter or a winged needle (not shown).
The structure of the syringe 300 is now described with reference to FIG. 13.
This syringe 300 has a cylindrical shape, so that an internal space which is defined by the piston 300d is filled up with the contrast medium. An injection port 300a having a tapered front end is provided on the forward end of the syringe 300. The syringe 300 is further provided on its rear end with a flange 300b and a pair of convex parts 300c, to be engaged with the injection head 10, which are provided on opposite positions.
On the rear side of the piston 300d, connection parts 300f to be connected with an oval connection part which is formed on the forward end of a plunger 11 provided on the injection head 10 are provided on positions rotated by 90.degree. with respect to the convex parts 300c to be opposed to each other.
With reference to FIGS. 14 and 15, attachment of the syringe 300 to the injection head 10 is now described.
As shown in FIG. 14, the injection head 10 is provided with an opening 12 having an inner peripheral surface 14. Convex parts 13 to be engaged with the convex parts 300c which are provided on the syringe 300 are provided on opposite positions of the inner peripheral surface 14.
Further, the plunger 11 is arranged in the opening 12, to be connected with the piston 300d of the syringe 300 for moving the piston 300d toward the forward end of the syringe 300.
The plunger 11 is provided on its forward end with a connection part including a neck portion which is smaller than the diameter of the plunger 11 and an oval head portion 11a, which is connected with the neck portion, provided with a curve portion having the same radius of curvature as the body part of the plunger 11.
In the injection head 10 having the aforementioned structure, the syringe 300 is inserted in the opening 12 so that the convex parts 300c provided on the syringe 300 are positioned in concave portions which are defined by the convex parts 13 provided on the opening 12 of the injection head 10, as shown in FIG. 14.
Thereafter the syringe 300 is rotated by about 90.degree. as shown in FIG. 15, whereby the convex parts 300c provided on the syringe 300 are positioned on rear sides of the convex parts 13 provided on the opening 12 so that the convex parts 13 of the opening 12 are engaged with the flange 300b and the convex parts 300c provided on the syringe 300, thereby fixing the syringe 300 to the injection head 10.
At this time, the head portion 11a provided on the plunger 11 is also connected to the connection part 300f which is provided on the piston 300d simultaneously with rotation of the syringe 300.
However, only the syringe 300 having the structure shown in FIG. 13 can be attached to the injection head 10 having the structure shown in FIGS. 14 and 15. On the other hand, a syringe 2 having a structure shown in FIG. 16 is also put on the market, in addition to that shown in FIG. 13.
The syringe 2 shown in FIG. 16 has a cylindrical body part 6, an injection port 7 which is provided on the forward end for injecting a contrast medium, and a flange part 5 which is provided on the rear end for defining an opening. Further, a piston 3 having a female screw 3a on the rear end of the syringe 2 is provided in the body part 6, so that an internal space which is defined by the piston 3 is filled up with a contrast medium 4.
When the syringe 2 shown in FIG. 16 can also be attached to the injection head 10 shown in FIGS. 14 and 15, therefore, it is possible to select two types of syringe shapes in the medical field, thereby improving handiness of persons concerned with medical treatment.